Regulating system



May 2, 197 v. s. L. BENDER REGULATING SYSTEM Filed April 12, 1966 United States Patent 3,316,846 REGULATING SYSTEM Vagn S. L. Bender, Nordborg, Denmark, assignor to DanfosskA/S, Nordborg, Denmark, a corporation of Denmar Filed Apr. 12, 1966, Ser. No. 542,037 priority, application Germany, Apr. 17, 1965,

Claims D 'l 4 Claims. c1.103-41 This invention relates to a regulating system for regulating the volume rate of delivery of a fluid from the discharge side of a pump means to a fluid dynamic system without significantly effecting the fluid pressure in the fluid dynamic system.

The expression fluid dynamic system, as used herein in the present specification and claims, refers to a system in which fluid flow occurs. Accordingly, the fluid dynamic system may be as simple as a single conduit or may be considerably more complex such as a plurality of interconnected conduits provided with valves. The invention will be. described herein with reference to a ffluid. Preferably, the fluid is aliquid. For example, the fluid dynamic system may be the lubricating passages or system of a machine, such as an engine, and the fluid, in this instance, would be a lubricating oil. The expression pump means used herein to denote that part of a pump which actually pumps, i.e., imparts energy to, a fluid, such as the gear and gear housing of a gear pump or the impeller and impeller housing of a centrifugal pump or the piston and cylinder of a piston pump, as distinguished from the other structure of the pump such as thatstructure defining an inlet conduit to and an outlet conduit from the gear or impeller housing or cylinder or the like.

. Commonly used are systems comprising a pump means,

first conduit means communicating between the suction side'of the pump means and a reservoir adapted to contairi a fluid, and second conduit means communicating between the discharge side of the pump means and a fluid dynamic system. The first and secondconduit means may sirhplybe the inlet and outlet, respectively, of the pump of which the pump means is the working portion or may be conduits external of the structure of the pump and communicating with the inlet and the outlet, respectively, of the pump.

In combination with such a system as above described, it' is known to provide a conduit communicating between the outlet and the inlet of the pump or, in more general terms, between the discharge and suction sides of the pump means, which conduit is provided with an adjustable throttle means such as throttle valve. This arrangement in effect short circuits a portion of the fluid discharged by the pump means back to the suction side of the pump means and thereby decreases the volume rate of delivery of the fluid from the discharge side of the pump means to the fluid dynamic system. However, there is a substantial loss of energy due to the pumping, short circuiting or recycling, and throttling of a portion of the fluid discharged from the pump means. Accordingly, whenever the proportion of the discharged fluid which is short circuited is increased or decreased, there is a corresponding respective decrease or increase in the pressure of the fluid which is delivered from the discharge side of the pump means to the fluid dynamic system, which causes a corresponding significant change in the fluid pressure in the fluid dynamic system.

Alternatively, above described, ing a portion of side of the pump means in response in combination with such a system as it is known to provide means for returnthe fluid discharged from the discharge means to the suction side of the pump to the pressureof the fluid in the fluid 3,316,846 Patented May 2, 1967 dynamic system. This arrangement provides substantially constant fluid pressure in the fluid dynamic system. However, with this arrangement it is not possible to regulate as desired the rate of delivery of the fluid from the discharge side of the pump means to the fluid dynamic system. In other words, in order to obtain a substantially constant fluid pressure in the fluid dynamic system, one sacrifices the prerogative of regulating the rate of delivery of the fluid from the discharge side of the pump means to the fluid dynamic system. This rate of delivery is, at any instant, determined by the level of the fluid pressure in the fluid dynamic system. Also, there is a substantial energy loss due to the pumping of that portion of the fluid which is returned to the suction side of the pump means. According to the present invention, there is provided, in combination with the basic system as above, described, a regulating system different from the regulating systems of the prior art above described. The new regulating system of the invention makes possible the regulation as desired of the rate of delivery of the fluid from the discharge side of the pump means to the fluid dynamic system without significantly effecting the fluid pressure in the fluid dynamic system. The expression without significantly effecting means that the fluid pressure in the fluid dynamic system remains substantially constant.

The regulating system of the invention essentially comprises an intermittently opening and closing fluid flow interruptor in communication with the discharge and suction sides of the pump means and a non-return valve means disposed downstream of the communication between the flow interruptor and the discharge side of the pump means and communicating between the discharge side of the pump means and the fluid dynamic system.

More specifically, the fluid flow interruptor of the regulating system of the invention has a fluid inlet and a fluid outlet, and in the regulating system there is provided conduit means communicating between discharge conduit means, the discharge conduit means communicating with the discharge side of the pump means, and the inlet of the fluid flow interruptor and conduit means communicating between the outlet of the fluid flow interruptor and the reservoir adapted to contain the fluid. The non-return valve means communicates between the discharge conduit means and the fluid dynamic system at a point downstream from the point of communication with the discharge conduit means of the conduit means to the inlet of the fluid flow interruptor. It is to be appreciated that all or any part of the regulating system of the invention may be mounted on or incorporated in the housing of the pump and, by virtue of such an arrangement, be considered to be part of the pump. Thus, for example, the conduit means and even the tfluid flow interruptor of the regulating system may be provided in the form of structure within the housing of the pump. Accordingly, while for illustrative purposes the conduit means of the regulating system are shown as elongated conduits, these conduit means may in fact constitute any arrangement providing the required communication.

The invention will now be further described by reference to the drawing, in which a preferred embodiment of the.

invention is shown schematically and in cross-section.

A pump 1, for example a gear pump, sucks a fluid (in this instance a liquid) from a reservoir 3 through a suction or inlet conduit 2a and discharges the fluid through a discharge or outlet conduit 2b to a fluid dynamic system 4, in this instance a simple conduit for transportation of the fluid. A short-circuit or recycle conduit 5 communicates between the discharge or pressure side of the pump 1, by communicating with the discharge conduit 2b, and the suction side of the pump 1, by communicating with the reservoir 3. The pump has a shaft 6 and is driven through the shaft 6 by conventional motor and linkage means which are not illustrated. The shaft 6 is provided with a clutch 7 of conventional construction. A non-return valve 8 of conventional construction is disposed to communicate between the discharge conduit 2b, at a point downstream from the short-circuit conduit 5, and the fluid dynamic system 4. The non-return valve 8 includes a spring 9 which is arranged to urge the valve into its seat against the flow from the discharge conduit 2b. The force With which the spring 9 urges the valve into its seat is pre-set so that the valve will not lift from its seat to permit passage of the fluid from the discharge conduit 2b to the fluid dynamic system 4 unless the pressure of the fluid in the discharge conduit 2b downstream from the short-circuit conduit exceeds a certain pre-determined value. It will be clear to those skilled in the art that this arrangement prevents return or reverse throw of the fluid from the fluid dynamic system or to the discharge conduit 2b. In the short-circuit conduit 5 is disposed a fluid flow interruptor 10 which is adapted to intermittently open and close to intermittently permit and prevent, respectively, flow of the fluid from the discharge side of the pump 1 to the suction side of the pump 1 through the short-circuit conduit 5.

The fluid flow interruptor 10 comprises a housing 11 which is closed by a lid 12, a first hollow cylinder 13 having four openings or passages 14 communicating between its interior and its exterior and a second hollow cylinder 15 having four openings or passages 16 communicating between its interior and its exterior. The hollow cylinder 13 is rotatably mounted in the casing 11 and can be engaged by the clutch 7 to be rotated by the shaft 6. The hollow cylinder 13 is fixed to the lid 12, against axial displacement, by the packing 18 :and the retaining ring 19. The hollow cylinder 15 is provided with a feather key 20 which is guided in a keyway 21 in the housing 11. Consequently, the hollow cylinder 15 is fixed against rotation relative to the housing 11 but can be displaced axially. For the purpose of providing means to axially displace the hollow cylinder 15, a threaded bore 23 is provided in the base 22 of the hollow cylinder 15 and a threaded spindle 24, having an adjusting lever 25, is provided to engage the threaded bore 23. The threaded spindle 24 is rotatably mounted in the front 26 of the housing 11. By rotating the threaded spindle 24 by means of the lever the hollow cylinder 15 is axially displaced.

In the lid 12 is provided a fluid inlet passage 27 communicating with an annular chamber or header 28. The hollow cylinder 13 is provided with four radial bores 29 communicating between the annular chamber 28 and an axial channel in the hollow cylinder 13. The axial channel 30 is sealed upstream from the radial bores 29 by means of a stopper 31. The axial channel 30 opens into the inner chamber 32 of the hollow cylinder 13. The passages 14 and 16 are disposed on a common circle so that upon rotation of the hollow cylinder 13 the passages 14 and 16 will periodically come into alignment with each other, whereby a communicating relationship therebetween is established. The passages 16 at all timescornrnunicate with the annular chamber 33 in the housing 11. Accordingly, when the openings 14 are in alignment with the openings 16, communication is established between the interior of the hollow cylinder 13, specifically the inner chamber 32 thereof, and the annular chamber 33. The annular chamber 33 communicates with axial channels 34 in the housing 11 and the axial channels 34 communicatewith an annular slot 35 in the housing 11. The annular slot 35 in turn communicates with a fluid outlet 36 in the lid 12. Thus, when the passages 14 are in alignment with the passages 16, communication between the interior of the hollow cylinder 13 and the fluid outlet 36 is established; this represents the open state or condition of the fluid flow interruptor 10, during which open state the fluid flows through the short-circuit conduit 5 from the discharge side of the pump 1 to the suction side of the pump 1. Conversely, when the openings 14 are out of alignment, i.e., totally out of alignment, with the passages 16, the fluid flow interruptor 10 is in its closed state or condition, in which closed state flow of the fluid through the conduit 5 from the discharge side of the pump 1 to the suction side of the pump 1 is prevented.

In the preferred embodiment, the passages 14 and 16 are of triangular cross-section and the triangular cross-section of each of the passages 14 is oriented differently from the triangular cross-section of each of the passages 16. Preferably, the triangular cross-section of each of the passages 14 is oriented in approximately 180 opposition to the triangular cross-section of each of the passages 16. In addition to this approximately 180 opposition in orientation, most preferably the triangular cross-sections are arranged symmetrically with respect to the common axis of the hollow cylinders 13 and 15. The purpose of such orientation and disposition of the cross-sections of the passages 14 and 16 is to permit particularly fine adjustment of the duration and magnitude of the open state of the fluid flow interruptor 10 by axial displacement of the hollow cylinder 15. It will be appreciated that by axially displacing the hollow cylinder 15 the extent to which the passages 16 align with the passages 14 may be adjusted or regulated. Thus, the greater the circumferential distance over which the passages 14 and the passages 16 are in alignment the greater the duration of the open state of the fluid flow interruptor 10. Also, the greater the integral sum of the products of the overlapping areas 37 (shaded) of the cross-sections of the passages 14 and 16 and the differential time intervals during which said overlapping areas exist, the greater is the magnitude of the open state of the fluid flow interruptor, i.e., the greater is the volume of flow of liquid through the fluid flow interruptor during its open state.

In the embodiment shown, the openings 14 in the hollow cylinder 13 are four in number and are circumferentially spaced from each other by and, likewise, the openings 16 in the hollow cylinder 15 are four in number and are circumferentially spaced from. each other by 90. Accordingly, when the hollow cylinder 13 is interconnected to the shaft 6 by means of the clutch 7 and the hollow cylinder 13 is therefore rotated once for each rotation of the gear wheelof the pump 1, upon each rotation of the hollow cylinder 13 the fluid flow interruptor is in its open state four times because the openings 14 come into alignment with the openings 16 four times. When the openings 14 and the openings 16 are not in alignment, the fluid flow interruptor 10 is in its closed state. When the fluid flow interruptor 10 is in its closed state, the fluid in the discharge conduit 2b immediately upstream from the non-return valve 8 is at a suflicient pressure to lift the valve from its seat and to, accordingly, enter the fluid dynamic system 4. When the fluid flow interruptor 10 is in its open state, the pressure of the fluid in the discharge conduit 2b immediately upstream from the non-return valve 8 is not of sufficient pressure to lift the valve from its seat and, accordingly, does not enter the fluid dynamic system 4. The rate at which the fluid is delivered from the discharge conduit 2b to the fluid dynamic system 4 is regulated by adjusting the duration and magnitude of the open states of the fluid flow interruptor 10 by means of axially displacing the hollow cylinder 15 to the desired position.

In the regulating system of the invention, the flow of the fluid through the short-circuit conduit 5 does not significantly influence the fluid pressure in the fluid dynamic system 4, because the non-return valve 8 is closed when the fluid is flowing through the short-circuit conduit 5. The only eflect upon the fluid pressure in the fluid dynamic system 4 is a minor, insignificant oscillation. Thus, when the non-return valve 8 opens the fluid pressure in the fluid dynamic system 4 will momentarily and slightly increase and closes the fluid pressure in the fluid slightly and momentarily decreases.

dynamic system 4 when the non-return valve 8 I These oscillations are of a scarcely perceptible magnitude because of the combination of factors comprising the inertia of the fluid in the fluid dynamic system and of any moving parts of the fluid dynamic system and the great frequency with which the state of the fluid flow interruptor is changed with respect to opening and closing. In any event, these oscillations can be damped by means of a conventional accumulator 38 in communication with the non-return valve 8. Thusfar in the present description of the invention, the fluid dynamic system 4 has been considered to start immediately downstream from the non-return valve 8. Therefore, the accumulator 38 as shown in the drawing would be considered to be in the fluid dynamic system 4. It should be understood, however, that in the case the accumulator 38 is used, the fluid dynamic system 4 could be considered to begin immediately downstream from the accumulator 38. In fact, it does not matter whether the accumulator 38 is or is not considered to be disposed in the fluid dynamic system 4; in either case, the accumulator 38 would be part of the regulating system of the invention. It only matters that the accumulator 38 be disposed downstream from and in communication with the non-return valve 8, in order that the accumulator 38 may cooperate with the non-return valve 8 in order to dampen fluid pressure oscillations.

The invention is not to be construed as limited to the particular forms disclosed herein, since these are to be regarded as illustrative rather than restrictive.

What I claim and desire to secure by Letters Patent is:

1. In combination with a system comprising pump means, first conduit means communicating between the suction side of said pump means and a reservoir adapted to contain a fluid, and second conduit means communicating between the discharge side of said pump means and a fluid dynamic system, the improvement comprising a regulating system for regulating as desired the rate of delivery of said fluid from the discharge side of said pump means to said fluid dynamic system without significantly effecting the fluid pressure in said fluid dynamic system, said regulating system comprising an intermittently opening and closing fluid flow interruptor having a fluid inlet and a fluid outlet, said fluid flow interruptor comprising a first hollow member having at least one passage of triangular cross-section communicating between its interior and its exterior and a second hollow member having at least one passage of triangularcrbsssection communicating between its interior and its exterior, said second hollow member being disposed interiorly of said first hollow member with the triangular cross-section of said at least one passage of said first hollow member being oriented differently from the triangular cross-section of said at least one passage of said second hollow member, one of said hollow members being rotatable to align said at least one passage of said hollow members in communicating relationship, conduit means communicating between said second conduit means and the fluid inlet of said flow interruptor, interconnection means for interconnecting said pump and said fluid flow interruptor for common driving thereof, means for adjusting the duration and magnitude of the opening of said fluid flow interruptor comprising means for axially displacing one of said hollow members to adjust the extent to which said at least one passages are alignable by rotating said rotatable hollow member, conduit means communicating between the fluid outlet of said flow interruptor and said reservoir, and non-return valve means communicating between said second conduit means and said fluid dynamic system.

2. A regulating system according to claim 1, further comprising an accumulator disposed downstream from and communicating with said non-return valve means.

3. A regulating system according to claim 1, in which the triangular cross-section of said at least one passage of said first hollow member is oriented in approximately opposition to the triangular cross-section of said at least one passage of said second hollow member.

4. A regulating system according to claim 3, further comprising an accumulator disposed downstream from and communicating with said non-return valve means.

References Cited by the Examiner UNITED STATES PATENTS 685,510 10/1901 Flint 137--637.4 2,433,954 1/ 1948 Lapsley 103--41 2,714,854 8/1955 Tyler 103-41 2,880,760 4/1959 Widell et al 137624.15 3,049,141 8/1962 Beatty 103-41 3,065,699 11/ 1962 Gromme 103-41 3,068,793 12/1962 Morris 103-41 3,157,173 11/1964 Martyn et al. 10 3--41 3,179,053 4/1965 Jordan 103-41 FOREIGN PATENTS 780,191 7/1957 Great Britain.

DONLEY J. STOCKING, Primary Examiner. MARK NEWMAN, Examiner. W. J. KRAUSS, Assistant Examiner. 

1. IN COMBINATION WITH A SYSTEM COMPRISING PUMP MEANS, FIRST CONDUIT MEANS COMMUNICATING BETWEEN THE SUCTION SIDE OF SAID PUMP MEANS AND A RESERVOIR ADAPTED TO CONTAIN A FLUID, AND SECOND CONDUIT MEANS COMMUNICATING BETWEEN THE DISCHARGE SIDE OF SAID PUMP MEANS AND A FLUID DYNAMIC SYSTEM, THE IMPROVEMENT COMPRISING A REGULATING SYSTEM FOR REGULATING AS DESIRED THE RATE OF DELIVERY OF SAID FLUID FROM THE DISCHARGE SIDE OF SAID PUMP MEANS TO SAID FLUID DYNAMIC SYSTEM WITHOUT SIGNIFICANTLY EFFECTING THE FLUID PRESSURE IN SAID FLUID DYNAMIC SYSTEM, SAID REGULATING SYSTEM COMPRISING AN INTERMITTENTLY OPENING AND CLOSING FLUID FLOW INTERRUPTOR HAVING A FLUID INLET AND A FLUID OUTLET, SAID FLUID FLOW INTERRUPTOR COMPRISING A FIRST HOLLOW MEMBER HAVING AT LEAST ONE PASSAGE OF TRIANGULAR CROSS-SECTION COMMUNICATING BETWEEN ITS INTERIOR AND ITS EXTERIOR AND A SECOND HOLLOW MEMBER HAVING AT LEAST ONE PASSAGE OF TRIANGULAR CROSSSECTION COMMUNICATING BETWEEN ITS INTERIOR AND ITS EXTERIOR, SAID SECOND HOLLOW MEMBER BEING DISPOSED INTERIORLY OF SAID FIRST HOLLOW MEMBER WITH THE TRIANGULAR CROSS-SECTION OF SAID AT LEAST ONE PASSAGE OF SAID FIRST HOLLOW MEMBER BEING ORIENTED DIFFERENTLY FROM THE TRIANGULAR CROSS-SECTION OF SAID AT LEAST ONE PASSAGE OF SAID SECOND HOLLOW MEMBER, ONE OF SAID HOLLOW MEMBERS BEING ROTATABLE TO ALIGN SAID AT LEAST ONE PASSAGE OF SAID HOLLOW MEMBERS IN COMMUNICATING RELATIONSHIP, CONDUIT MEANS COMMUNICATING BETWEEN SAID SECOND CONDUIT MEANS AND THE FLUID INLET OF SAID FLOW INTERRUPTOR, INTERCONNECTION MEANS FOR INTERCONNECTING SAID PUMP AND SAID FLUID FLOW INTERRUPTOR FOR COMMON DRIVING THEREOF, MEANS FOR ADJUSTING THE DURATION AND MAGNITUDE OF THE OPENING OF SAID FLUID FLOW INTERRUPTOR COMPRISING MEANS FOR AXIALLY DISPLACING ONE OF SAID HOLLOW MEMBERS TO ADJUST THE EXTENT TO WHICH SAID AT LEAST ONE PASSAGES ARE ALIGNABLE BY ROTATING SAID ROTATABLE HOLLOW MEMBER, CONDUIT MEANS COMMUNICATING BETWEEN THE FLUID OUTLET OF SAID FLOW INTERRUPTOR AND SAID RESERVOIR, AND NON-RETURN VALVE MEANS COMMUNICATING BETWEEN SAID SECOND CONDUIT MEANS AND SAID FLUID DYNAMIC SYSTEM. 